Question

Section: Name: Date: Lab Partner: Questions (a) Give the equation for the reaction of concentrated H2SO, with prope (b) What is the formula of the product obtained from the reaction of dilute H2SO4 with propene? 2. You have a hydrocarbon unknown which is insoluble in concentrated H2SO4. What conclusion do you draw? 3. You have an unknown which may or may not be a hydrocarbon. It gives a negative test with Bry/CHCI, but decolorizes KMnO4. (Both results are correct.) What can you infer about your unknown? 124

Answer 1

The answer to the question 1 (a and b) have been explained as below,

2. In general, the alkene hydrocarbons consisting of hetero atoms (xoygen and nitrogen) are soluble in conc. H₂SO₄ by addition reaction.

DATE Da Remetion of propone with canch, sou conc. product Addition by Markonikov fashian b.) Reaction with dilute Hasou Hsou tho HotUSOL Thentar hydration of alkene is the only breaction as below.. TH produt The abition is by Markonikov fashion .

As the unknown do not react with conc. H₂SO₄ therefor the unknown may be belong to the alkane hydrocarbon or alkyl halide which do not have solubility in conc. H₂SO_4.

_{3. The Br2/CHCl3 is one of the test to check the unsaturation simply by addition of bromine in alkene or alkyne. But this bromine test is not full proof because some alkene or alkynes react very slowly or show negative test by colour change observation of bromine, alkane also react slowly with Br2. At the end the test shows negative.}

_{If the bromine test is negative the next full proof confirmation test of alkene or alkyne is KMnO4 complete oxidation of alkene and alkyne give diol and diacids as complete oxidation product with change in the colour of KMnO4 solution form purple to brown. KMnO4 also give positive test with aldehydes, formic acid and formate ester because of complete oxidation reaction.}

_{The another test for unsaturation to check is Iodine test which give confirm results.}

_{As the observation here is negative Br2/CHCl3 test and decolorizes KMnO4 therefore unknown may be the class of hydrocarbons containing alkene or alkyne or aldehyde or formaic acid or formic acid esters.}